U.S. patent application number 11/738550 was filed with the patent office on 2008-10-23 for compressed fuel product using flax straw derivative.
Invention is credited to Kevin D. Lumb.
Application Number | 20080256851 11/738550 |
Document ID | / |
Family ID | 39870793 |
Filed Date | 2008-10-23 |
United States Patent
Application |
20080256851 |
Kind Code |
A1 |
Lumb; Kevin D. |
October 23, 2008 |
Compressed Fuel Product Using Flax Straw Derivative
Abstract
A compressed fuel product, for example a firelog or other like
product, comprises a material comprising a flax straw derivative,
for example flax shives or other material derived from flax, which
is compressed into a solid body. The material is bonded together
under pressure into the solid body solely by natural lignin in the
flax straw derivative.
Inventors: |
Lumb; Kevin D.; (Brandon,
CA) |
Correspondence
Address: |
ADE & COMPANY INC.
2157 Henderson Highway
WINNIPEG
MB
R2G1P9
CA
|
Family ID: |
39870793 |
Appl. No.: |
11/738550 |
Filed: |
April 23, 2007 |
Current U.S.
Class: |
44/605 |
Current CPC
Class: |
Y02E 50/30 20130101;
C10L 5/44 20130101; Y02E 50/10 20130101; C10L 5/365 20130101 |
Class at
Publication: |
44/605 |
International
Class: |
C10L 5/00 20060101
C10L005/00 |
Claims
1. A compressed fuel product comprising a material compressed into
a solid body, the material comprising a flax straw derivative.
2. The product according to claim 1 wherein the material primarily
comprises a flax straw derivative.
3. The product according to claim 1 wherein a majority of the
material comprises a flax straw derivative.
4. The product according to claim 1 wherein the material consists
only of a flax straw derivative.
5. The product according to claim 1 wherein the flax straw
derivative consists only of flax shives.
6. The product according to claim 1 wherein the material consists
only of flax shives.
7. The product according to claim 1 wherein the material in the
solid body is bonded together solely by natural lignin in the flax
straw derivative.
8. The product according to claim 1 wherein the solid body has a
specific gravity greater than 1.
9. The product according to claim 1 wherein the solid body has a
specific gravity near 1.25.
10. The product according to claim 1 wherein the solid body is
formed in the shape of a firelog.
11. A method of forming a compressed fuel product comprising
providing a material comprising a flax straw derivative and
compressing the material into a solid body.
12. The method according to claim 11 wherein the material primarily
comprises a flax straw derivative.
13. The method according to claim 11 wherein a majority of the
material comprises a flax straw derivative.
14. The method according to claim 11 wherein the material consists
only of a flax straw derivative.
15. The method according to claim 11 wherein the flax straw
derivative consists only of flax shives.
16. The method according to claim 11 wherein the material consists
only of flax shives.
17. The method according to claim 11 including bonding the material
together in the solid body solely by natural lignin in the flax
straw derivative.
18. The method according to claim 11 including compressing the
material until the solid body has a specific gravity greater than
1.
19. The method according to claim 11 including extruding the
material through an extruder having a screw press and heating the
material as it is extruded solely by friction generated from
rotating the screw press.
20. The method according to claim 11 including forming the solid
body in the shape of a firelog.
Description
[0001] This application claims foreign priority benefits from the
corresponding Canadian Patent Application, of the same title, filed
Apr. 13, 2007.
FIELD OF THE INVENTION
[0002] The present invention relates to a compressed fuel product,
for example a firelog, fuel pellets, briquettes or wafers and the
like, and more particularly relates to a compressed fuel product
which comprises a flax straw derivative.
BACKGROUND
[0003] It is known to modify natural fuels such as wood products
and the like to improve the burning characteristics thereof. For
example it is known to manufacture a fire log comprising various
wood products which are densified and compressed into a solid body
using waxes, resins or other additives other than natural cellulose
material to both improve the burning of the material and the
bonding of the finished compressed product. Known additives are
typically costly and in addition are generally considered to be not
environmentally friendly.
[0004] U.S. Pat. Nos. 6,113,662 to Sprules and 4,478,601 to
Stephens disclose examples of compressed fuel products in which
combustible materials are compressed into a solid body requiring
bonding agents to form the finished product. U.S. Pat. No.
4,553,978 to Yvan discloses an example of a fuel product which does
not make use of additional waxes or binders, however the resulting
product is instead highly friable as it may be broken up by hand
due to its small specific gravity in the order of 0.25. Due to the
characteristics of the finished product according to the techniques
of Yvan, the resulting product is unusable as a fire log as the
product is not sufficiently durable. U.S. Pat. No. 2,177,557
discloses a further example of fuel product, however the product
relies on alcohols and other additives in order to function
properly so that the product is both costly to manufacture and
results in undesirable fumes.
SUMMARY OF THE INVENTION
[0005] According to one aspect of the present invention there is
provided a compressed fuel product comprising a material compressed
into a solid body, the material comprising a flax straw
derivative.
[0006] According to second aspect of the present invention there is
provided a method of forming a compressed fuel product comprising
providing a material comprising a flax straw derivative and
compressing the material into a solid body.
[0007] Use of a flax straw derivative for forming a compressed fuel
product results in the product being formable into a fire log or
other compressed solid body without the addition of any other
waxes, resins or bonding type agents being required as the natural
lignins in the flax straw derivative are sufficient to effect
bonding of the log into the desirable solid body. The resulting
composition of the log is therefore environmental friendly while
being both simple and low cost to manufacture.
[0008] The material may primarily comprise a flax straw derivative
as a majority thereof, but preferably the material consists only of
a flax straw derivative.
[0009] Preferably, the flax straw derivative consists only of flax
shives in which the shives consist of the remainder of flax straw
once the fibrous material has been removed. The flax straw
derivative used in the present invention however may comprise flax
straw in its entirety, with or without the flax seeds, and with or
without fibrous material known to be extracted from the flax straw.
The flax straw derivative may further comprise parts of flax seed,
for example seed hulls or other remnants resulting from the removal
of flax oil from the flax.
[0010] The method of forming the compressed fuel product preferably
includes bonding the material together in the solid body solely by
natural lignin in the flax straw derivative.
[0011] Preferably the material is compressed until the solid body
has a specific gravity greater than 1, and more preferably
approximately 1.25.
[0012] The method may include extruding the material through an
extruder having a screw press and heating the material as it is
extruded solely by friction generated from rotating the screw
press.
[0013] Preferably the solid body comprises a firelog.
[0014] One embodiment of the invention will now be described in
conjunction with the accompanying drawings in which:
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] FIG. 1 is a perspective view of a compressed fuel product
according to the present invention.
[0016] FIG. 2 is a schematic view of the process for forming the
compressed fuel product.
[0017] FIG. 3 is a plan view a site for effecting the process of
FIG. 2.
[0018] FIG. 4 is an enlarged plan view of a portion of the site
plan according to FIG. 3.
[0019] FIG. 5 is an enlarged plan view of a cooling section of the
site plan according to FIG. 3.
[0020] FIG. 6 is a partly sectional side schematic view of one of
the extruders for forming the compressed fuel products.
[0021] In the drawings like characters of reference indicate
corresponding parts in the different figures.
DETAILED DESCRIPTION
[0022] Referring to the accompanying figures there is illustrated a
compressed fuel product generally indicated by reference numeral
10. In the illustrated embodiment, the product 10 is formed in the
shape of a fire log and consists solely of flax shives so that the
completed compressed fuel product has a specific gravity in the
order of 1.25. No additional waxes or bonding agents are included
as the natural lignin in the flax shives provides sufficient
bonding to maintain the fuel product compressed as a single body
once heated and compressed under considerable pressure.
[0023] Prior to formation of the compressed fuel product 10,
harvested flax is first processed to remove the seeds and is then
subsequently processed at a plant 12 to remove fibrous material
from the straw so that only the shives remain. The flax shives are
then transported from the processing plant 12 to the site
illustrated in FIG. 3. The flax shives are transported by trailers
14 which feed the flax shives into an unloading hopper 16 at the
site. An auger 18 carries the flax shives from the unload hopper to
a blower 20 which conveys the shives into a wet storage bin 22 on
the site.
[0024] When it is desirable to form the compressed fuel product,
the flax shives are carried from the storage bin 22 by an auger 24
to a dryer 26 which dries the shives to a moisture content of
approximately 4% to prepare it for subsequent processing. The dryer
26 is heated by raw flax material being burned in a suitable burner
68. A cyclone 28 assists in subsequently carrying the material from
the dryer 26 to a dry storage area 70.
[0025] A plurality of feed augers 32 in the dry storage area 70
feed the flax shives into a series of extruders 30 supported in
parallel with one another where the compressed fuel product is
extruded therefrom to respective log cutters 34 which cut the
compressed fuel product into individual logs deposited on a
conveyor belt 36.
[0026] Once formed into individual logs, the compressed fuel
product is delivered by the conveyor belt 36 to an outdoor cooling
building 38 prior to packaging. The cooling building 38 includes a
cooling belt 40 which conveys the product 10 along multiple passes
in front of cooling fans 42 which cool the product. The product is
then returned indoors for being deposited on a receiving table
44.
[0027] From the receiving table 44, the product 10 is either loaded
onto bulk pallets 46 or the product is placed in cardboard grocery
trade boxes 48 in quantities of six per box. When packaged in
grocery trade boxes, fire starter 50 is packaged with the logs with
the boxes being subsequently taped by an automatic taper 52 before
being loaded onto pallets 54 which are subsequently wrapped by a
suitable wrapper 56 for placement either in storage 58 on the site
or onto carrier trucks 60 for delivery.
[0028] The bulk pallets 46 are also wrapped by a suitable automatic
wrapper 62 for either being placed in storage 64 or for being
loaded onto carrier trucks 66 for subsequent delivery.
[0029] Turning now to the extruders 30 in more detail as shown in
FIG. 6, each extruder 30 includes an inlet hopper 70 which receives
the flax shives for distribution to the inlet of a screw press 72.
The screw press 72 feeds the flax shives through a surrounding
barrel 74 to force the shives under pressure through a die 76 which
continuously extrudes the compressed fuel product consisting solely
of flax shives therefrom. The screw press 72 is tapered to be
reduced in diameter towards the die 76. An internal cooling jacket
is provided surrounding the barrel prior to the die 76.
[0030] Sufficient pressure is generated by the screw press 72 which
in turn provides sufficient heat by friction that the natural
lignins in the flax shives cause the flax shives to be bonded
together to form the finished compressed fuel product. The cutters
34 form the individual fire logs from the continuously extruded
material exiting the extruder.
[0031] As described above flax straw derivative, comprising either
whole flax straw including both shives and fiber or just flax
shives, is bonded into a compressed fuel product using pressure,
heat and natural lignins of the flax to effect the bonding. To
begin the process, the raw, screened material is first received in
a walking floor trailer with a moisture content of about 10 to
12%.
[0032] The unloading hopper receives the bulk flax straw at a rate
of about one tonne per minute.
[0033] The raw material is augured out of the bin and deposited
into either a blower or a screw auger that carries the straw up to
the top of the 100 tonne "wet" bin. The raw flax straw is metered
out of the 100 tonne bin at a consistent rate of approximately six
tonnes per hour. The material is fed into a horizontal continuous
run dryer. The dryer is fueled by a bio-fuel burner 68 that is
supplied with dried flax straw that has already passed through the
dryer.
[0034] A suction fan that is creating negative pressure in the
dryer actually pulls the flax straw through the dryer & then
through a cyclone. The cyclone is used to separate the flax straw
from the air created by the fan.
[0035] The dried flax straw now falls to the bottom of the cyclone
through a rotary gate & drops in to an auger that will carry
the dried material into a dry bin 70 inside the building.
[0036] The dry bin 70 in the manufacturing plant has a live bottom
floor. This means that the bottom of the bin is mostly covered with
the screw feed augers 32 to draw the product out at a very precise
& even rate. This is the metering system that controls the flow
of raw, dried material into the densified log extruder. Once the
product is augured out of the dry bin it is transferred via another
screw auger to the hopper on to of the extruder.
[0037] The raw, dried material is now gravity fed from the extruder
hopper down into the extruder itself.
[0038] The extruder, powered by a 100 horse power electric motor,
consists of a receiving chamber, screw, barrel, and forming
die.
[0039] The receiving chamber is the area around the tail end of the
extruder screw that allows the initial course flights of the screw
to pick up material. The flax straw is then forced into the barrel
of the extruder. The material is starting to pack in the barrel.
The screw, turning at about 300 rpm continuously pushes more
material into the barrel and then forces it into the die. The die
forms the material into a round log about 4 inches in diameter with
diametrically opposed flat sides of approximately 1.5 inches in
width.
[0040] The screws of the extruders are operated to generate heat to
achieve temperatures in the range of 300 to 350 degrees Fahrenheit
by friction alone. This heat is sufficient to effectively melt the
natural lignins in the flax straw to successfully glue the logs
together without the addition of any glues, waxes, or resins of any
kind.
[0041] The end product is a densified, all natural 4 inch diameter
fire log, ten to twelve inches long weighing about 5 pounds with a
specific gravity of around 1.25.
[0042] Since various modifications can be made in my invention as
herein above described, and many apparently widely different
embodiments of same made within the spirit and scope of the claims
without department from such spirit and scope, it is intended that
all matter contained in the accompanying specification shall be
interpreted as illustrative only and not in a limiting sense.
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